Anvil construction



2 Sheets-Sheet 1 Filed Sept. 19, 1958 Dec. 6, 1960 w. c. QUEDNAU ANVILCONSTRUCTION ZZ/aZZerC. Quednazb, k W Q?- ANVIL CONSTRUCTION Walter C.Quednau, Berkeley, illl., assignor to Acme Steel Company, Chicago, Ills,a corporation of Illinois Filed Sept. 19, 1958, Ser. No. 762,122

4 Claims. (Cl. 1-2) This invention relates to improvements in wirestapling machines of the kind that automatically drive and clinchstaples formed in the machine from wire segments cut from a Continuouswire supply. More particularly, the present invention is directed to ahighly improved anvil for use in machines of this type.

In automatic wire stapling machines of the kind just mentioned, wire isintermittently advanced into the machine to a position wherein theinnermost end portion of the wire lies across or through a slot in ananvil used in the formation of the staples. When the wire has reachedthis position a cutter automatically severs the end portion of the wirefrom the wire supply and a staple forming device then comes into contactwith the severed wire segment to bend the same over the anvil to form astaple, the opposite ends of the severed segment becoming the legs ofthe staple. A driving member thereupon moves toward the head of thestaple, first displacing the anvil from its staple supporting position,and then contacting the newly formed staple to drive it through awork-piece.

I In automatic machine operation of the kind just stated a seriousproblem arises in gripping the relatively short segment of wire andretaining the same in proper position on the anvil during the briefperiod that elapses between the time when the segment is cut from thewire supply and the time when it is contacted and bent over the anvil bythe staple forming member. In normal operation this time lapse may beonly a fraction of a second, but the vibration of the machine and theoperation of the cutter are such that the severed segment will oftenslip or move with respect to the anvil during this interval, causing animproperly shaped staple to be formed unless the segment is firmlyretained in its proper position on the anvil.

Previously used means for retaining the segment in proper position onthe anvil during this period have comprised spring-pressed fingers builteither into the anvil itself or constructed and positioned externally ofthe anvil so as to grip the segment before it is severed and thereafterretain the segment until it is subsequently contacted by the stapleforming or driving members.

Externally disposed springpressed fingers or plungers have not affectedthe strength of the anvils with which they have been employed, but ino'rder that a machine embodying an externally disposed finger or plungermay be used to manufacture and drive staples of different widths it hasbeen necessary that the finger or plunger be mounted in such a way thatit could be moved from one position to another when an anvil of adifferent width was employed. The external finger or plunger requiredpositioning close to an anvil for narrow widths to insure contact withthe short wire segment and another positioning for the manufacture ofstaples of wider width to prevent the wider anvil from interfering withthe ex ternal plunger or finger-like wire gripping means. The need forrepositioning the external wire gripping means requires the use ofspecial parts and is consequently Patented Dec. 6, 1960 undesirable instandardized machines capable of forming and driving staples of avariety of widths. In addition, externally disposed spring-pressed wiregripping fingers or plungers are made as small as possible so as tointerfere with the work-piece as little as possible. They are thereforenecessarily relatively weak, and because they must be placed in thevicinity of the workpiece, they are subject to being broken and bent bythe work-piece and otherwise rendered inoperative because of dirt orother foreign material present in the work region. There is also anotherdisadvantage of the ordinary type externally disposed spring-pressedwire gripper; it grips by pressing against the upper surface of one endof each staple wire segment passed through the wire receiving groove ofthe anvil to cause the wire segment to be tilted slightly from itsnormal path through the groove and thereby frictionally held between theupper surface of the groove on one end and its lower surface on theother end. This manner of gripping has proven only satisfactory. itrequires that the wire cutting members which sever the segment from themain length of wire be sharp, otherwise, with dull cutting members thesevering more nearly resembles a pinching action which causes thesevered segment to jump forward and be displaced as it is cut because itis not gripped tightly enough. This is a deleterious condition whichrequires more fre quent replacement of the cutting members than wouldordinarily be expected.

Certain types of internally disposed spring-pressed wire grippers havebeen used with varying degrees of success.

There is a form of this type using a positively actuated plunger whichis positively cleared of the path of the wire to allow for thepresentation to the anvil of the wire segment, after which the plungeris released to let it grip the wire under the force of spring pressure.This type of plunger has had the disadvantage of being complex becauseits operation must be linked to and timed properly with the otheroperative parts of the stapling or stitching machine.

It is therefore the principal object of this invention to provide animproved anvil construction in a stitching machine of the type referredto, which obviates the difficulties and shortcomings mentioned for priorart devices.

In order to accomplish this object, it is a further object of theinvention to provide an improved anvil construction wherein the gripperis of the internally spring biased type and not an integral part of theanvil portion over which the wire segment is bent into a U-shape, is onewhich is separated by the action of the wire itself camming against itduring wire feed, is one which does not require an excessively strongspring so that even light guage wire will not buckle when fed into theanvil, but which can use a spring strong enough to prevent slippage ofthe wire segment during wire cutting to thereby prolong the useful lifeof the wire cutting parts, and which is extremely simple in design sothat it can be manufactured inexpensively and assembled easily andquickly. I

In order to provide such an improved anvil, it is another object of thisinvention to provide a gripper in the form of a rod protruding at itsouter end into the wire receiving slot of the anvil, the rod beingconnected at its inner end to an enlarged portion. against which aspring reacts to urge the gripper forward of the anvil, the enlargedportion being mounted relative to the rod and positioned in a recess inthe anvil in such a manner that the gripper is urged angularly by thespring to urge its outer rod end into the path of the wire receivingslot where it frictionally grips a wire segment positioned therein, therod portion being of circular cross-section to provide a curved camsurface against which the wire being fed can react to deflect thegripper and permit access of the wire into the wire receiving slot inthe anvil.

These and other objects and advantages of the present invention will beapparent from the following description of certain preferred embodimentsthereof, taken with the accompanying drawings wherein:

Fig. l is a perspective and exploded view of one form of the improvedanvil;

Fig. 2 is an elevation of an automatic wire stitching machine of a kindin which the anvil of Fig. 1 may be employed;

Fig. 3 is a fragmentary elevational view, partly in crosssection, of thelower portion of the machine of Fig. 2, showing the relative position ofthe anvil and the staple forming means of the machine after the staplehas been formed over the anvil but before driving the staple has begun;

Fig. 4 is a cross-section taken substantially along the line 44 in Fig.2, showing a length of wire in the anvil before the forming operationhas begun;

Fig. 5 is a fragmentary elevation of the rear side of the lower portionof the machine;

Fig. 6 is a top plan view of the anvil of Fig. 1;

Fig. 7 is a side view thereof;

Fig. 8 is a front view of the anvil;

Fig. 9 is a longitudinal cross-section taken substantially along line 99in Fig. 5 showing the interior construction of the anvil;

Fig. 10 is a lateral cross-section taken substantially along line Ill-10in Fig. 6.

The anvil of the present invention in its first embodiment, is shown indetail in the drawings in Fig. 1 and in Figs. 6 to 10. As thereillustrated, the anvil comprises a generally cylindrical body 30, ofmild steel or the like, having two parallel planar work surfaces 31formed on its opposite sides adjacent its forward end which, for thesake of clarity in description, will be called its nose or working end.A transverse open slot 32, preferably of rectangular cross-section, isprovided in this working end of the anvil body and extends from one worksurface 31 to the other, the longitudinal axis of the slot being normalto both surfaces. From a level slightly above the slot 32, the upperportion of the working end of the anvil body extends upwardly andrearwardly in an inclined planar. surface 33. That portion of the end ofthe anvil body below the slot, on the other hand, is curved downwardlyand rearwardly as at 34 and converges smoothly with the generallycylindrical main portion of the anvil body. The effect of thisconstruction is to provide the front of the anvil body with a forwardlyextending nose-like arrangement having the transverse slot 32 formedtherein into which stapling wire may be fed endwise in the directionshown by the arrow 35 in Fig. 1. In order to make it easier to feed thewire into the slot, the upper wall of the slot at one end thereof may bebeveled upwardly as at 32a (Fig. 8) in order to provide a larger mouthfor the slot.

The wire stapling machine in which this particular form of the anvil maybest be employed, and the manner in which the anvil performs in themachine, will be described presently. At this point in the description,however, it will suffice to state that after a length of wire 36a hasbeen fed endwise into the slot 32 to substantially the position shown bythe straight broken lines in Fig. 1, with a portion of the wireextending from the opposite ends of the slot 32, the wire is cut orsevered from the Wire supply and a staple former is thereupon downwardlyin straddling fashion alongside the working surfaces 31 to bend theprotruding ends of the Wire downwardly to form a staple having legs 36b.During this operation, it will be seen that the portion 36c of the wirecontained within the slot 32 becomes the crown or upper portion of thenewly formed staple.

The anvil body 30 is hollow and, as will presently be explained, itforms a shell for contents that act forcibly to retain or grip thelength of wire 36a in the slot 32 during the severing and bendingoperations just referred to.

The anvil body 30 is provided with a cylindrical bore 37 extendingaxially inwardly from the rear end 38 thereof to a point short ofshoulders 39 that define the innermost vertical edges of the workingsurfaces 31 on the sides of the body. The inner end 40 of the bore isflat and intersects an open slot 41 cut into the front portion of theanvil body 30 below the level of the wire receiving slot 32. The slot isdefined by two parallel walls 42 and 43. This slot 41 extends into theanvil body to a region beyond the inner end 40 of the bore 37 andterminates at an inner end 44. When positioned properly in the stitchingmachine, a pin 45 provided in the frame 49 of the machine acts as a stopto limit the inward travel of the anvil body 30. Positioned in the bore37 is the wire gripper 46 which comprises an enlarged cylindrical innerend 46a of slightly smaller diameter than the bore 37. This inner end46a is ordi: narily urged forward of the anvil body 30 by means; of acompression spring 46b which reacts between the inner end 46a and acover plate 71 which is fastened to the frame member 49 by means of fourscrews 71a. A raised projection 71b is provided in the plate 71 to keepthe spring 46b in alignment. The forward surface of the end 46a of thewire gripper 46 is secured slightly below center to a smaller diametercylindrical rod 46c which protrudes forward through the slot 41 whereits free end 46d terminates in the region of the wire receiving slot 32of the anvil. This rod 46c is slightly curved concavely upward with theresult that it normally urges the enlarged end 46a to be displacedangularly from the bottom surface 40 of the bore 37 in the region 72.This angular displacement provides a degree of angular movement of theentire wire gripper which is resisted by the force of the spring 46b,but which enables the rod end 46d to be urged by the force of the spring46b into wire gripping position as shown in Fig. 9 against the. lengthof wire 36a.

The automatic wire stitching machine in which the anvil just describedmay best be used is illustrated in Figs. 2 to 5. Machines of thisgeneral type are well-known in the art and need not be described ingreat detail here; The machine comprises a pair of feed rollers 47 eachof which is mounted on a shaft 48 rotatably carried on a. supportingplate or frame member 49. The rollers 47 are rotated in synchronism andin opposite directions by a gear 50, carried and driven by a drive shaft50a (Fig. 4), and by a pinion 51 which meshes with a gear 52 carriedupon the back of the right-hand roller 47 as seen in Fig. 2. This lattergear meshes with an identical gear 52 carried on the back of the otherroller. The drive shaft 50a is operatively connected to a driving motoror other source of power, not shown.

Each roller 47 has a peripheral cam 53 formed thereon, with feeding ofthe staple wire 36 between the rollers 47 taking place when portions ofthe cams 53 are opposite each other. A detailed description of theoperation of these rollers 47 and their earns 53 may be found in US.Patent No. 2,199,241. It will suffice here merely to state that therollers act to advance the wire 36 intermittently, once upon eachcomplete cycle of the machine. The wire 36 from the feed rollers 47enters awire guide 54 having a passage therein for slidably re-' ceivingthe wire and directing the same to a'wire cutting device indicatedgenerally by the numeral 55. During its passage through the wire guide54 the wire may pass under a wire check 56 of the kind described indetain in US. Patent No. 2,478,397.

The plate or frame member 49 has formed thereon a pair of upright spacedprojections 57 and 58 which constitute a guideway for a verticalreciprocating sliding block 59 that has a pair of staple formers 60 and61 formed on its lower end in spaced apart relation. Retention of theblock 59 between the projections 57 and 58;

is accomplished by a cover plate 62 extending across and secured to theprojections 57 and 58 by screws 63. The sliding block 59 is reciprocatedby means including a cam member 65 mounted upon the inner end of thedrive shaft 50a. A cam groove 65 in the cam is adapted to receive aroller 66 carried on the sliding block 59 adjacent its upper end. FromFigs. 2 and 4 it will be understood that the block 59 completes adownward stroke and returns to its uppermost position once during eachcomplete revolution of the cam 64.

Slidably supported between the staple formers 60 and 61, forreciprocating movement is a staple driver 67 that is pivotally connectedadjacent its upper end to one end of a connecting link 68 (Fig. 4) whichhas its opposite end rotatab ly supported upon a stub shaft 69 fixedupon the forward face of the cam member 64 in a position offset withrespect to the axis of the drive shaft 50a. It will thus be seen thatthe staple driver 67 is reciprocated upwardly and downwardly as theshaft 50a revolves. The arrangement of the parts is such that the feedrollers 47, the staple formers 60 and 61, and the staple driver 67 areoperated in a timed relation, with each being moved through a completecycle during one revolution of the shaft 50a.

The anvil described above is located in the machine between the plateprojections 57 and 58, and below the staple driver 57, in a path thatlies between the staple formers 60 and 61. The anvil is slidablysupported in a round transverse opening 70 (Fig. 4) in the frame member49.

The wire 36 from the wire guide 54 passes through a cutter tube 75carried in the plate projections 58, the staple former 61 being providedwith a longitudinal groove 77 for slidably receiving the extendedinnermost end 76 of the cutter tube. A cutting tool 78 is mounted on thelower end of the staple former 61 for reciprocal movement therewith in apath across the end 76 of the cutter tube 75, the Wire 36 being cut bythe tool 78 as the tool passes across the wire opening in the cuttertube.

In the operation of the stitching machine just described the wire 36 isfed by the feed rollers 47 through the guide 54 and the cutter tube 75into the transverse slot 32 in the anvil while the staple formers 60 and51 and the staple driver 67 are in their uppermost positions as shown inFig. 2. The cylindrical rod portion 460 is of sufficient diameter thatno more than its upper one-half protrudes into the slot 32 when no wireis present. Since this upper one-half has a curved surface, it presentsa camming surface against which the leading end of the wire can react inorder to deflect the rod portion 46c downward and clear of the slot 32and thereby permit passage of the wire into the slot 32. Upon completionof the feeding operation, the staple formers and the staple driver aremoved downwardly by the cam 64. In the initial phase of this downwardmovement the block 59, and the staple formers 60 and 61 that are formedthereon, descends at a rate more rapid than that of the staple driver.As the staple formers 60 and 61 approach the length of wire 36acontained in the slot 32 of the anvil, the cutting tool 78 severs thewire as it passes the end 76 of the cutting tube 75. The cutting of thelength of wire 36a in this operation, however, does not disturb ordislodge the wire from the slot 32 because it is firmly gripped or heldtherein by the outer end of the rod portion 460. The length of wire 36ais thus retained in its proper position on the anvil, and when thestaple formers 60 and 61 contact the wire, the ends of the wireprotruding from the slot 32 are bent downwardly along the workingsurfaces 31 on the sides of the forward end of the staple body, theprotruding ends of the length of wire 36a becoming the legs 36b of anewly formed staple. The legs 36b of the formed staple are thereuponretained in slots 60a and 61a (Fig. 3) provided in the staple formers 60and 61, respectively, while the staple driving member 67 drives thestaple.

' As the staple driver approaches its driving position the lower edgethereof strikes the oblique surface 33 on the front of the anvil body30, forcing the anvil body rearwardly in the opening 70 against thecompression of the spring 46b. Inasmuch as the legs 36b of the newlyformed staple are retained in the slots 60a and 61a in the stapleformers 60 and 61, this rearward movement of the anvil body 30 withdrawsthe anvil from the staple, the force against the oblique surface 33 ofthe anvil being sufiicient to overcome the grip of the rod portion 46dpressing the formed staple against the anvil. The staple driver thencontacts the crown 36c of the newly formed staple and drives itdownwardly into a carton or other work piece.

A member 80 (Fig. 4) is pivoted at 81 to the staple formers 60 and 61for pivotal movement therebetween, the members 80 being yieldablymovable to a position between the staple formers by a spring-pressedmember 82 movably carried on the cover plate 62. The pivoted member 80provides a support to prevent the staple legs from bending inwardlytoward each other during the staple driving operation. The member 80 ispivoted outwardly from between the staple formers by the driver 67 as itapproaches its lowermost position during the downstroke.

Although only one specific embodiment of the invention has been shownand described, it should be apparent to those skilled in the art thatvarious changes may be made in construction without departing from thetrue scope of the appended claims.

I claim:

1. In combination with a wire stitching machine having wire feedingmeans, means for cutting said Wire and a staple former, an anvilcomprising, an anvil body adapted to coact with said staple former inthe formation of staples, said body having a fixed open transverse slotin one end thereof for receiving a length of wire fed by said wirefeeding means, a wire gripper within said body biased by a spring urgingthe wire gripper into wire gripping position against a length of wirefed into said open transverse slot by said feeding means, said wiregripper having a wire gripping portion which is curved in crosssectionto provide a wedge shaped wire entry between the wire gripper portionand one wall of said open transverse slot on the wire inlet side tothereby enable the end of the wire fed endwise by said wire feedingmeans to cam said Wire gripper portion clear of the open transverse slotand allow passage of the Wire into the open transverse slot.

2. In combination with a wire stitching machine having wire feedingmeans, means for cutting said wire, a staple former, and an anvilcomprising, an anvil body adapted to coact with said staple former inthe formation of U-shaped staples, said body having a fixed dimensionopen transverse slot in the forward end thereof for receiving a lengthof wire fed by said wire feeding means, a wire gripper contained by saidbody and provided with a rigid rod having a free end and another endsecured to a plunger positioned at the bottom of a bore provided in therear end of said body, said plunger being angularly positioned relativeto the bottom of said bore when the rod is gripping a length of wire, aspring reacting against the plunger and urging it into a position ofsmaller angular relation with said bottom to thereby urge said free endof said rod into a position intersecting said open transverse slot toblock the passage of wire thereto.

3. In combination with a wire stitching machine having wire feedingmeans, means for cutting said wire, a staple former, and an anvilcomprising, an anvil body adapted to coact with said staple former inthe formation of U-shaped staples, said body having a fixed dimensionopen transverse slot in the forward end thereof for receiving a lengthof wire fed by said wire feeding means, a wire gripper contained by saidbody and provided with a rigid rod having a free end and anotherend'secured to a plunger positioned at the bottom of a bore provided inthe rear: end of said body, said plunger being angularly positionedrelative to the bottom of said bore when the rod is gripping a length ofwire, a spring reacting against the plunger and urging it into aposition of smaller angular relation with said bottom to thereby urgesaid free end of said rod into a position intersecting said opentransverse slot to block the passage of wire thereto, the rod having acam surface against which the leading end of wire fed by said wirefeeding means can react to displace the Wire gripper against thepressure of said spring and permit the passage of the wire into the opentransverse slot. I

4. In combination with a wire stitching machine having wire feedingmeans, means for cutting said wire, a staple former and an anvilcomprising, an anvil body slidable in the frame of the stitching machinebetween a wire receiving position and a retracted position and adaptedto coact with said staple former in the formation of U-shaped staples,said body having a fixed dimension open transverse slot in the forwardend thereof for receiving a length of wire fed by said wire feedingmeans and a longitudinal bore in its rear end extending partiallythrough the length of the body and another opening providing a passagebetween the slot and the bore, a wire gripper contained by said body andprovided with a rigid at the bottom of the bore with the rod extendingthrough said passage with its free end intersecting the open transverseslot in the wire feed path, the plunger being urged against the bottomof the bore by a compression spring which is mounted to react betweenthe frame of the wire stitching machine and the plunger for urging thefree end of the rod into wire gripping position, said spring also urgingslidable movement of the anvil body along the frame into its wirereceiving position, the curvature of the rod acting as a cam surface forcausing the Wire gripper to be deflected angularly bodily from the Wirepath to a wire gripping position when wire is fed endwise into thetransverse slot, this deflection causing the plunger to be positioned ata different angle relative to the bottom wall of the bore.

References Cited in the file of this patent UNITED STATES PATENTS

